Well, you could just be dilated on the ouside, but the internal OS might still be nice and closed. Doesn't matter if the external OS is a bit dilated as long as the inner in shut...you are 33 weeks so even if you are dilated 1cm I don't think that's that big of a deal...could be like that right up until you go into labor! My second pregnancy at 28 weeks I had dilated to 2.5 but stayed that way until a week or so before delivery. This pregnancy my internal OS is still tightly closed and cervix is still long, although on the outside I am a bit over 1cm dilated but that is normal if you have had previous pregnancies...I would ring your OB or midwife and let them know what you found just to ease your mind! Honestly being that your 33 weeks if it was me I wouldn't really worry if it was just 1cm!
